I'm new to gardening in Austin, TX. I planted snapdragons, petunias, and pansies in the fall. They all made it through winter and were looking great the last month. In the last couple of weeks my snapdragons' flowers have started dying off. I've been watering every other day and feeding with the liquid feed. One of the snapdragons had a mold-looking like thing on it. I don't know if they all "disease" or what's going on with them. Any suggestions?